Tooth facing



G. COUTlF TOOTH FACING Aug. 16, 1927.

Filed Jan. 14. 1927 Patented Aug. 16,1927.

. UNITED STATES PATENT OFFICE.

, GEORGES COU'TII, OF PARIS, FRANCE.

f TOOTH` FACING.

Application l'ed Jammin, 1827-, Serial bridges',v caps and plates.

, :A primary object of theinvention. is provision of `an improved tooth-facing of very light andl thin structure lcomprising hno gingival bevel or protuberance whereby its outer face can evenly merge with the facey of thek @um and-thus absolutely givethe ap pea-rance lof a natural tooth.

A further object of the invention the` provisionof a ltooth-facing the anchorage of which on lthe metallic bridge, eap or plate is performed by improved dovetailed means whereby said tooth-facing is'. more securely held in position Y A still furtherobjgect of the invention is the provision. of an armouredtooth-faeing embodying a metallic lining wherein the anchoragexdovetailed means are formed before the porcelain vfacing proper is .moulded thereon.

A stillV further'obj'eet of the inventionis the;.provision of improved means for shaping the metalli-@lining preparatory to the moulding of the porcelain body. 1 of the toothfacing.. j f 1 Vith the above and such otherobjeets in View as will incidentally yappear hereafter,

theinvention Aconsists of the' novel devices and: combinations of devices andy methods that `will now bedescribed with referencev to the-draw'mg and. defined'inthe claims'.

In the accompanying drawing Figure 1, is an elevational view on'` a very large scale of an ineisor` tooth-facing according' to the: invention, viewed internally so as to Vdisclose its lanchoring dovetailed groovev f v f VFigureQ a longitudinal sectional view thereof. -j f f Figure4 is' laI front elevational View on a. smaller scale of a metallic molar support showingits anchoring dovetail'ed key. Figure 4 is an edge view thereof;V Y Figure 5! is a. planfview thereof more clearlyshowing the shape of the key,

f Figures 6,' Z and 8 illustrate on a -smallv l scale. and viewed from dierent positions the No. 161,114, aniin Innes. latch 5, 1986.

die for manufacturing tooth-facings l.as showninFiiguresl and2.. .A v g As illustrated in Figures 1 and 2, the iin-- proved tooth-facing aecording'to the` inven-- tionj isY constituted by a cap-like or boodlke hollow member theouter front or visible Wall 1 of which presents externally the Y size, shape and colour, of .a normal ytooth whereby when in position upon'a metallic bridge, cap or plate (not shown) itwillhave the appearance of such a tooth., The outer wall of thisvrtoothffacing l is rednced in thixclmess at its lower endas at 1a i'. e. cuit according to such a sharpy bevel-shapeas will permit it when in wearing position up om the metallic: ysupport to evenly merge With-.the faceofthe underlying gum (not shown)4 so as te avoid any protuberance or projection as in, similar tooth'facings as proposed heretofore.

The Wall l isA elbowed at its crown end to forni. a rearwardly extending bevelled exten,- sion 11" for delineatinga recess 2 which tapers and is undercut. as at The inner face of said wall l is formed with a longitudinal groove 4 undercut'.Y ad:vr 5 along yeach :of its longitudinal edg for providing a dovetailed Saat., This groove 4 is. fairly widev at itslower' end i. e. at the mouth Aof the toothfacing and it, upwardly tapers in Width whilst downwardly tapering indepth whereby it has a maximum width amd a minimum adjacent said month The .progresduction and also talpermit a' new tootlfacing to be readily fitted vand fixed in position should have beenbrokeman such l' tooth-feelings being 'thus rendered interchangeable. 'f

Suchl toothefaeingsi be made lof porone represented in Figures 6, 7 and S is used. Said die is supported by a base 8 of conventional shape and size and `it is .-provided with a rounded or convex shape substantially corresponding to the one of the recess to be formed in the hollow toothfacing. It is furthermore surmounted by a dovetailed rib or ridge 9 having a tapering outline as clearly shown in Figure 6 i. e. such an outline as to taper in width in the one direction whilst tapering in thickness in the other direction. Thanks to this shape of the die 7, a thin sheet of metal or gauzesuch as platinum or gold may be applied upon the tapering ridge 9 andstamped or pressed into a correspondingly tapering shape so far as its groove is concerned. Such a sheet of precious metal having a dovetailed groove gradually reduced in width in the one direction whilst being gradually reduced in thickness in the opposite direction is afterwards used as a support for the porcelain or like body of the tooth-facing l which may be moulded, cast and secured thereon by the customary proc esses as used inthe dental art whereby a tooth-facing internally reinforced or armoured by a precious metal lining is obtained. ln the case of a gold lining, it may after having had the porcelain body moulded thereon be chemically removed by rubbing same with aqua regia or removed in a different way, wherebyl a tooth-facing entirely made of porcelain is finally obtained.

- A tooth-facing as represented in Figures l and 2 and manufactured as has just been described with reference to Figures 6, 7 and 8 is adapted to beused in conjunction with a metal denture, crown, cap, bridge, vplate or other support i. e. applied externally on said support for concealing any metalfpart l and giving the appearance of a natural tooth whilst ensuring the dental advantages of a metal crown or bridge. Towthat end, the metal g support l0 presentingfthe general shape of an incisor, molar or other tooth (see Figures 3, 4 and 5 wherein is illustrated Y by way of example a small molar support) is formed or provided on its. outer face with a dovetailed key l1 the tapering shape -of which is adapted to lit the oneof the corresponding groove or seat tvformed in the tootlnfacing 1. By this arrangement, an anchoring effect is obtained owing to the wedging engagement of the keyll in the seat 4. If required, said anchoring effect maybe supplemented by interposingV athin'layer of cement or like binding substance between the porcelain tootlrfacing and its metal support.

Owing to the particular undercut shape of the recess 2 formed in the tooth-facing l and to the peculiar tapering shape of its dovetailed groove, it will be held very securely in position either in the longitudinal or in the transverseV direction irrespective of the cutting, tearing, chewing or other strains undergone by the tooth and its support.

It vwill `belunderstood that depending on the kind of teeth to be provided with toothfacings, the size of the said facings andv particularly of their rearwardly extending crown parts 1b will vary. Similarly the size and shape of the die 7 same requirement.

W'hat'l claim is l. A porcelain tooth-facing comprising an outer front wall progressively reduced in thickness from its crown to its mouth for will vary to suit the merging with the gingival face, a rearward I recess delineated by said front wall and rearward extension, and a dovetailed groove formed heightwise in the back face of said A front wall and having a depth gradually decreasing from crown to mouth and a width decreasing from mouth` to crown, the narrower and deeper portion of said dovetailed groove coinciding with the undercut portion of the recess in the tooth-facing.

8. A tooth-facing comprising in combination, on the onehand, a porcelain front wal-1 gradually decreasing in thickness fromits crown lend to its mouth end for merging with the face of the underlying gum, ka rear# ward crown bevelled extension integral with said wall, an undercut recess delineated by said wall and extension, anda dovetailed groove formed heightwise in thebackv face of said wall and having a depth 'gradually decreasing from crown to mouth and awidth decreasing from mouth to crown and, on the other hand, an armouring metal liningof equivalent grooved shape fixedly'l secured to the back face of the porcelain front wall.

4l. The vmethod of manufacturinga toothfacing of the type set forth consisting to use a suitably shaped and sized die having to stamp or press a sheet of precious metal or gauze on said die for forming a tapering dovetailed groove therein and to mould porcelain or a simil-ar substance on said metal sheet according to a progressively reduced sectional shape for providing a thin bevel adjacent the mouth of the tooth-facing.

5. The method of manufacturing a toothfacing according to claim 4 further consisting to chemically remove its inner metallic l0 armouring plate forv example made of gold by dissolving same out by means of aqua regia.

In testimony whereof I aiiix my signature.

s GEQRGES Courir.A 

